Sodium hypochlorite (NaOCl) is effective for fighting against various viruses and bacteria, and solutions formed from sodium hypochlorite, e.g., bleach, are extensively adopted in various environments, utensils or foods with disinfection requirements. For example, solutions formed from sodium hypochlorite are applied to household cleaning, hospital disinfection, tableware or medical equipment disinfection, and food process bleaching. However, in bleach, the concentration of sodium hypochlorite needs to have different specified values in response to different application requirements. The concentration that is too low may fail to effectively provide adequate disinfection result, while the concentration that is too high may be hazardous to human bodies. Therefore, there is a need for measuring such concentration of the solution.
For example, in the U.S. Pat. No. 7,283,245, a system for measuring the concentration of multiple chemical or biological substances is disclosed. In the above disclosure, a disposable optical test element and a spectroscopic detector are adopted. The disposable optical test element is provided with a specific testing film having a constant spectrum reaction standard corresponding to a specific analyte. Through a change in light absorbance, luminescence, or other light-based forms of the specific analyte to the disposable optical test element, the spectroscopic detector detects the optical responses of the specific analyte to the disposable optical test element. Based on the spectrum reaction standard corresponding to the testing film, the concentration of the specific analyte can be measured. Thus, to measure the concentration of the sodium hypochlorite, the corresponding disposable optical test element is utilized.
The above optical measurement system is extremely costly. Further, the optical measurement system needs to be additionally connected to a computer in order to analyze the concentration of the analyte, in a way that a value of the concentration cannot be instantly obtained. As a result, the above optical measurement system may be inconvenient when being put to application.